Small and easy to understand codebase perfect for extending and building upon.
For a more comprehensive solution, have a look at
Requests which is also powered by urllib3.

What’s wrong with urllib and urllib2?

There are two critical features missing from the Python standard library:
Connection re-using/pooling and file posting. It’s not terribly hard to
implement these yourself, but it’s much easier to use a module that already
did the work for you.

The Python standard libraries urllib and urllib2 have little to do
with each other. They were designed to be independent and standalone, each
solving a different scope of problems, and urllib3 follows in a similar
vein.

Why do I want to reuse connections?

Performance. When you normally do a urllib call, a separate socket
connection is created with each request. By reusing existing sockets
(supported since HTTP 1.1), the requests will take up less resources on the
server’s end, and also provide a faster response time at the client’s end.
With some simple benchmarks (see test/benchmark.py
), downloading 15 URLs from google.com is about twice as fast when using
HTTPConnectionPool (which uses 1 connection) than using plain urllib (which
uses 15 connections).

This library is perfect for:

Talking to an API

Crawling a website

Any situation where being able to post files, handle redirection, and
retrying is useful. It’s relatively lightweight, so it can be used for
anything!

Contributing

Check for open issues or open
a fresh issue to start a discussion around a feature idea or a bug. There is
a Contributor Friendly tag for issues that should be ideal for people who
are not very familiar with the codebase yet.

1.6 (2013-04-25)

Contrib: Optional SNI support for Py2 using PyOpenSSL. (Issue #156)

ProxyManager automatically adds Host: ... header if not given.

Improved SSL-related code. cert_req now optionally takes a string like
“REQUIRED” or “NONE”. Same with ssl_version takes strings like “SSLv23”
The string values reflect the suffix of the respective constant variable.
(Issue #130)